gprofng: need to know that experiment was created on big-endian machine

gprofng: need to know that experiment was created on big-endian machine

gprofng/ChangeLog
2025-06-25  Vladimir Mezentsev  <vladimir.mezentsev@oracle.com>

	* configure.ac: Add AC_C_BIGENDIAN.
	* common/config.h.in: Rebuild.
	* configure: Rebuild.
	* libcollector/collector.c (log_header_write): Save big-endian flag.
	* src/DbeSession.h (is_bigendian): New function.
	* src/DbeSession.cc: Likewise.
	* src/Experiment.cc: Set 'bigendian' and 'need_swap_endian'.
	* src/Experiment.h: New field 'bigendian'.
	* src/LoadObject.cc: Remove an unused variable.
	* src/LoadObject.h: Likewise.